The present invention relates to a cursor position control device of the type commonly referred to as a trackball device. Such devices are used, for example, to control the movement of a cursor of a video display as in a video game.
Trackball devices include a housing having a circular opening therein and a plurality of rotatable supports, at least two of which are respectively rotatable about perpendicular axes. A ball is loosely seated on the supports, with a portion of the ball projecting through the opening so that the user can manually rotate the ball. The rotatable supports respectively respond to corresponding components of rotational movement of the ball. The supports are respectively connected to reader means which produce signals indicative of the speed and direction of rotation of the supports. The two perpendicular supports respectively correspond to the x and y directions of the movement of the cursor so that speed and direction of movement of the cursor in the x and y directions correspond respectively to the speed and direction of rotation of the associated supports.
In prior trackball devices, the components thereof have been arranged so as to necessitate a large housing. Furthermore, prior trackball devices have not completely solved the problem of friction in the rotation of the supports while still addressing the problem of rattling and poor shock and impact resistance.